|Strongest monster||Troll brute, Troll shaman and Troll chucker|
The Abandoned Burthorpe mine was once inhabited by Dwarves, but in time it was deserted for reasons unknown. Since then it has become the home of a number of Mountain trolls. It is in Burthorpe, as its name suggests, and it can be found north of the Troll Invasion minigame.
Inside it is filled with Troll brutes to the west, Troll chuckers to the north, and Troll shamans to the east. Corporal Boothe, with his store Burthorpe Guard Quartermaster, stands little ways from the mouth of the cave selling some basic equipment. There is an inaccessible tunnel at the opposite end of the cave; examining it gives the message "It's too dangerous to go deeper."
The mine was formerly involved in the Troll Warzone tutorial, and it was here that Morningstar was fought. Although he is no longer found there, his bones (Troll general's bones) spawn in the northern room with the Troll chuckers for players who have defeated him. Similarly, Troll lieutenant's bones spawn in the eastern cave with the shamans.
- For two weeks after an update on 9 June 2014, several sections of the cave were height mapped, inclining up to 20 tiles. This was caused by Mod Labl neglecting to revert his "tests".